There are more than 6,000 diseases classified as rare (defined as having a prevalence in the United States of <200,000 persons). While individually these entities are uncommon, as a group they are an important cause of chronic illness, disability, and premature death in both children and adults. Despite their rarity, many fundamental advances in medicine have come from the study of rare diseases and these have benefited common diseases. Both because of currently inadequate therapy and the potential to assist common as well as rare disorders, the conduct of clinical research in rare diseases is essential. In order to assure the future of this research, the training of the next generation of investigators in this field is important. The NIH Rare Diseases Clinical Research Network (RDCRN) is an ideal group to sponsor a conference addressing rare disease research methodology that would supplement general training in clinical research and attract trainees and junior faculty into this important field. In 2007 the RDCRN held the inaugural Conference on Clinical Research for Rare Diseases (CCRRD). This Conference, supported by an R13 grant was a tremendous success, attracted 200 attendees, fulfilled all the goals of the Organizing Committee and NIH sponsors, and received outstanding scores on evaluations. This initial meeting success was continued in 2010 and 2012 when the second and third CCRRDs were held, again supported by an R13 grant. This R13 grant proposes to continue supporting the Conference on Clinical Research for Rare Diseases in 2016, 2018, and 2020. These Conferences will provide information and resources to trainees and junior faculty that they can directly apply to their work and career development. The proposed conference format is of a full day program made up of short didactic lectures, panel discussions, and break-out sessions on focused areas relevant to the attendee's current stage of career and research development. The issues that will be addressed include: 1) creating research networks, 2) novel study designs and biostatistical approaches when s in dealing with small number of subjects, 3) use of big data in the study of rare diseases; 4) working with the FDA and industry; 5) collaboration between investigators and patient advocacy groups in rare diseases research; 6) patient-reported outcomes in research; and 7) career development and mentoring. There will also be poster presentations so that trainees can share their current research with each other and with senior investigators of the RDCRN and receive feedback. The final session will be a trainee networking session. Members of the RDCRN Steering Committee (Consortia PIs, NIH program officials from multiple institutes, and patient advocacy group representatives) will participate in the conference. There will be an evaluation component where participants will fill out a form indicating the level of success in achieving our goals. Finally, the proceedings will be posted on the web and a summary article will be published.